JK Rowling and the dangerous leap: Harry Potter author hopes to be just as successful with 5m deal to write first novel for adults

New phase: JK Rowling is writing a new novel for adults

Millions of children have been bewitched by her literary magic – now JK Rowling is to write her first book for grown-ups.

However the Harry Potter author, who is worth more than 530million, is keeping her fans guessing about the characters and plot of her new book.

She said: ‘Although I’ve enjoyed writing it every bit as much, my next book will be very different to the Harry Potter series.

‘The freedom to explore new territory is a gift that Harry’s success has brought me.’

The Potter books were published by Bloomsbury, but Miss Rowling said that it was ‘logical’ to have a new publisher for her adult work and has switched to Little, Brown.

Industry insiders estimate the deal is worth more than 5million and it is expected the new book will be released later this year.

A spokesman for Waterstones said: ‘JK Rowling’s audience is vast and her position is unique. The Harry Potter books were a global success and her fans are very loyal.

‘Children that were eight, nine, or ten when the books first came out in the 1990s are now in their 20s. Plenty of adults loved the books regardless of whether they had children, so the potential market for her is huge.’

The seven Harry Potter books, which inspired a movie franchise, have sold more than 450million copies worldwide.

The final instalment, Harry Potter And The Deathly Hallows, was published in 2007 and sold 11million copies on its first day.

Will JK's new novel have the same mass appeal as Harry Potter

Last year she launched the Pottermore.com website, which is effectively a virtual wizarding world offering users encyclopaedic detail about the original books.

Millions registered to join it and access material about the key characters in Harry Potter that had been previously unpublished.

Miss Rowling also uses the interactive site to sell the e-book versions of her hugely popular books.

The Harry Potter books have sold about 450 million copies worldwide and for more than a decade each installment became the must have book in publishing.

Her final Harry Potter novel, 'Harry Potter and the Deathly Hallows,' was published in 2007. It sold 11 million copies on the first day.

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The books spawned a hit movie franchise, which made stars of the three leads Daniel Radcliffe, Emma Watson and Rupert Grint.

The author has already produced two spin-off books raising thousands for charity, Fantastic Beasts and Where to Find Them, and Quidditch Through the Ages.

A lavish theme park opened last year, while branded fashion and merchandise is worth millions.

Thousands have taken to Twitter to debate the new project.

One fan said: ‘I am so excited that JK Rowling is writing a new novel. I don’t care if it is not Potter related. This is brilliant, brilliant news.

Another added: ‘I have only just heard about plans for a new book and I am already gripped. Imagine what’s going to happen when it actually comes out.’